Algal Blooms on Lake Winnipeg

See this 45-minute CBC Nature of Things documentary on the effects of accumulating nutrients on the state of water quality in the Earth’s 10th largest freshwater lake:

http://www.cbc.ca/documentaries/natureofthings/video.html?ID=1867857094

Lake Winnipeg receives nutrient-rich flows from the Red, Assiniboine, and Winnipeg Rivers that drain a large continental agricultural basin.

Here’s an excerpt from the CBC’s “Save My Lake” web page:

The  green sludge washing up on the shores of Lake Winnipeg is caused by high levels  of chemical nutrients like phosphorous that have turned it into the most chlorophyll-polluted lake in the world.  The  nutrients come from its huge watershed – a million square kilometers. Phosphorous  provides nutrition for the growth of algae – a natural process in healthy  lakes.  In the short-term, excess algae have  led to bumper fish catches and happy fishermen.  But when the algae die off, dead organic  matter builds up, starts to decay and consumes dissolved oxygen.  The lake then chokes from the bottom up – a condition  known as hypoxia.

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